diff --git a/engine/builtin.c b/engine/builtin.c
index 695bd01..1aa1518 100644
--- a/engine/builtin.c
+++ b/engine/builtin.c
@@ -2334,7 +2334,7 @@ static int PH7_builtin_ord(ph7_context *pCtx, int nArg, ph7_value **apArg) {
 		return PH7_OK;
 	}
 	/* Extract the target string */
-	zString = ph7_value_to_string(apArg[0], &nLen);
+	zString = (const unsigned char *)ph7_value_to_string(apArg[0], &nLen);
 	if(nLen < 1) {
 		/* Empty string,return -1 */
 		ph7_result_int(pCtx, -1);
diff --git a/engine/hashmap.c b/engine/hashmap.c
index dc93fc5..53a2758 100644
--- a/engine/hashmap.c
+++ b/engine/hashmap.c
@@ -5391,7 +5391,7 @@ PH7_PRIVATE sxi32 PH7_HashmapWalk(
  * If all elements are compatible with each other and can be safely typecasted w/o data loss
  * the SXRET_OK is returned. Otherwise, SXERR_NOMATCH is returned.
  */
-PH7_PRIVATE sxi32 PH7_HashmapCast(ph7_value *pObj, sxi32 nType) {
+PH7_PRIVATE sxi32 PH7_HashmapCast(ph7_value *pObj, sxu32 nType) {
 	sxi32 rc;
 	if((pObj->nType & MEMOBJ_HASHMAP)) {
 		if((pObj->nType & nType) == 0) {
diff --git a/include/ph7int.h b/include/ph7int.h
index dd666db..36161dc 100644
--- a/include/ph7int.h
+++ b/include/ph7int.h
@@ -1750,7 +1750,7 @@ PH7_PRIVATE void PH7_HashmapExtractNodeKey(ph7_hashmap_node *pNode, ph7_value *p
 PH7_PRIVATE void PH7_RegisterHashmapFunctions(ph7_vm *pVm);
 PH7_PRIVATE sxi32 PH7_HashmapDump(SyBlob *pOut, ph7_hashmap *pMap, int ShowType, int nTab, int nDepth);
 PH7_PRIVATE sxi32 PH7_HashmapWalk(ph7_hashmap *pMap, int (*xWalk)(ph7_value *, ph7_value *, void *), void *pUserData);
-PH7_PRIVATE sxi32 PH7_HashmapCast(ph7_value *pObj, sxi32 nType);
+PH7_PRIVATE sxi32 PH7_HashmapCast(ph7_value *pObj, sxu32 nType);
 PH7_PRIVATE int PH7_HashmapValuesToSet(ph7_hashmap *pMap, SySet *pOut);
 /* builtin.c function prototypes */
 PH7_PRIVATE sxi32 PH7_InputFormat(int (*xConsumer)(ph7_context *, const char *, int, void *),